package com.example.mobile2021606177cke0615;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import java.util.ArrayList;
import java.util.List;

public class MyDataAdapter {
    private MySQLiteOpenHelper openHelper;
    private SQLiteDatabase database;
    public void openDB(Context context){
        openHelper=new MySQLiteOpenHelper(context,"student.db",null,1);
        try{
            database=openHelper.getWritableDatabase();
        }catch (Exception e){
            database=openHelper.getReadableDatabase();
        }

    }
    public void closeDB(){
        if(database!=null){
            database.close();
            database=null;
        }
        if(openHelper!=null){
            openHelper.close();
            openHelper=null;
        }

    }

    public List<Users> QueryAll(Context context){
        List<Users> usersList=new ArrayList<>();
        openDB(context);
        Cursor cursor = database.query("users", null, null,
                null, null, null, null);

        if(cursor.moveToFirst()){
            do{
                int id=cursor.getInt(0);
                String name=cursor.getString(1);
                int age= cursor.getInt(2);
                float score=cursor.getFloat(3);
                usersList.add(new Users(id, name, age, score));
            }while (cursor.moveToNext());
        }
        cursor.close();
        closeDB();
        return usersList;
    }
}